Friday, August 31, 2018

This picture of BMSB was taken in Dallas Countyin 2017 by Annika Linkqvist and
posted on iNaturalist. Note the white bands on
the antennae.

Brown marmorated stink bug has been causing a stink, literally, in many parts of the country for the past 15 years or so. It feeds on important crops, and finishes up its dirty work by invading homes in the fall. It's the complete pest. Bad for farmers and homeowners alike.

Now the BMSB may be making a new home in Texas. According to EDDMaps distribution records, this stink bug has now been confirmed in four Texas counties. Two sightings were recorded last summer in Dallas County by the same observer, and one in Collin County in 2015. It has also been seen in Harris and Ft. Bend counties in the Houston area. To our knowledge there have been no reports of buildings being invaded or plant damage.

I live in Collin County and have yet to see a BMSB; but that doesn't mean they're not here, slowly reproducing and hiding out until they make their grand entrance. When they do, chances are that a pest control company will be the first to know.

I first posted about this pest 7 years ago, before any sightings in the Houston or Dallas area. Given these recent reports, I think its time to renew the call to vigilance.

Identification

So how do you identify BMSB? First, it is a stink bug (family Pentatomidae), all of which have flattened, shield-like bodies with a triangular plate in the middle separating the bases of the two wings. The BMSB is brown, about 17 mm-long (2/3 inch), and may produce a musty scent when disturbed. Several other stinkbugs look similar to BMSB. Identify by looking for three characters: First is the white band at the joint between the 3rd and 4th (last) antennal segments (see image). Second is the shoulders: the BMSB also has rounded shoulder angles (corners of the pronotum at the widest part of the body) compared to other stink bugs with pointed shoulder angles or jagged teeth above the shoulder. Last, there are four creamy spots on the pronotum (shield) just behind the head and on the top of the scutellum (triangular shaped plate between the bases of the wings).

The brown marmorated stink bug (Halyomorpha halys, right) can be distinguished from the brown (Euschistus servus, left) and bark (Brochymena quadripustulata, center) stink bugs by markings and the white bands at the joints of the antennae. (Note: These images not necessarily to scale. The two left photos were taken by Mike Quinn, TexasEnto.net; and the right image by Melinda Fawver. Thanks for permission to use.)

What to do

If you think you've run into an infestation of brown marmorated stink bugs, let me or one of our extension entomologists from around the state know. To confirm, we will need specimens or good quality digital images. If you choose to send a specimen, please follow the directions on this page, and include a completed insect ID form with accurate information about date and location where the specimen was collected.

We are especially interested if the bugs are damaging fruit (fruit, corn, grapes, tomatoes, beans) or coming to lights and invading homes in large numbers. If you have a good picture and want to report an infestation, you can also report to our national EDDMaps database at http://www.eddmaps.org/bmsb/report/.

This insect has the potential to become a major headache for households and businesses, as well as farmers. It reminds me of my latest proverb: "If you crave job security in your career, go into highway construction or pest control." Just as there will always be highways being repaired, there will always be new pests to battle. Brown marmorated stink bug is a good example.

Thursday, August 9, 2018

Who wants to eat insecticide? Not me, and I'm guessing certainly not your customers.

So if your company does residential pest control, are your employees trained to know what to do when they encounter a vegetable garden, fruit or nut tree in a backyard? And are they trained to answer a customer's questions about the safety of their insecticides around vegetables or herbs?

Do your employees know what to do when encountering vegetables, herbs or other food plants around a home? Asking a customer about their edible plants might save that account. Photo by Jeff Raska.

I'm guessing this subject is not commonly addressed in technician training classes. I was asked by an industry sales representative this week: "Is it appropriate for a technician to be recommending that a homeowner simply wash their vegetables after having their yard treated for mosquitoes, or should the vegetables should be thrown away?"

The answer to this question depends on whether the plants were directly exposed to the spray and what the label says.

I did a quick review of the common mosquito adulticides used in backpack sprayers. None of them allow application to edible plants. The Suspend® Polyzone label, for example, says “do not apply this product to edible crops.” The Fendona® label says to not use on vegetable gardens. Some make no mention of vegetables or edible crops at all. And when it comes to edible plants, if application is not explicitly mentioned, it's not allowed.

Will pesticides make a plant toxic?

Of course many insecticides, including some of the active ingredients in your tool kit, are used legally on crops all the time by farmers. This is allowed by the EPA only if that pesticide has been granted a tolerance for a given crop, and certain days-to-harvest intervals are followed. These rules work to ensure that any pesticide residues left after a pesticide application are below levels of concern for human health. The 2016 Pesticide Data Program survey by USDA shows that this system works. Out of 10,000 market food samples analyzed in the study, over 99 percent had residues well below the EPA
established tolerances. More than 23 percent had no
detectable pesticide residue.

So insecticide residues on plants are not necessarily toxic, especially when label directions are followed and adequate time passes to allow the product to naturally degrade. The products we use in pest control may be the same active ingredients used by farmers; but they may differ in concentration and formulation. Most importantly, pest control insecticides do not carry food-treatment labels so they cannot legally be used on edible crops.

Talstar® products, for example, consist of the active ingredient bifenthrin, the same active ingredient used by farmers and even home gardeners under a variety of trade names. The Talstar® P label for mosquito control, however, says "not to apply to bearing fruit or nut trees or vegetables or edible crops." To a law judge it won't matter whether other formulations allow application to food crops. To a judge enforcing FIFRA requirements, you must follow the label on the product you are using.

Spray contamination

If an insecticide is deliberately sprayed on an edible crop or plant, and the product is not labeled for such use, the plant would not considered safe by EPA standards. The implication is that all of the plant, or at least the edible parts, should be thrown away. Your customer could replant, of course, unless prohibited by the label.

Backpack mistblowers are commonly used
for applying residual insecticides to mosquito
resting sites; but mists should be applied carefully
to avoid drift onto fruit and nut trees and
vegetable gardens.

Labels generally do not, however, prohibit use of these products in the vicinity of a vegetable garden. I assume this means that if you take care to keep sprays directed away from vegetable gardens, any incidental drift from nearby spraying with a coarse spray, aerosol or mist generator equipment should not be a problem. Likewise, thermal foggers and ULV applications used nearby should leave insignificant residues as long as the application orifices are directed away from edible plants at all times.

Of course applicators should always be aware of weather conditions and the locations of edible plants. If wind is blowing toward a garden, upwind applications should be avoided.

So what should you do if a fruit, nut, vegetable or herb is is accidentally over-sprayed? Such a plant should be pulled, or else the produce should be left uneaten or discarded, by the customer.

Systemic insecticides

Some insecticides are "systemic," meaning they have enough water solubility to be taken up by plant roots and translocated to other parts of the plant. Although the EPA allows some systemic insecticides on crops, in general systemics are not labeled for use on food crops because they can leave residues in edible plant tissues that do not quickly degrade.

Insecticides containing neonicotinoids and acephate are examples of PMP insecticides that may be systemic in plants. These include products like Merit®, Premise®, Transport®, Tandem®, Alpine®, Temprid®, Orthene® and others. Herbs and other root or leafy vegetables exposed to systemic insecticides should be considered contaminated for the season and should not be consumed.

Some termiticides can also be systemic in plants, leading to concerns about vegetable gardens planted next to homes treated for termites. Fipronil, for example, is slightly systemic in some plants; and the Termidor® SC label says not to "apply around edible plants." The label does not say explicitly how far away an edible plant must be, although the Premise® 2 label (whose active ingredient, imidacloprid, is much more water soluble) is more specific. It says to "not treat within a distance of one foot out from the
drip line of edible plants." The Premise® guideline, therefore, is probably a good, conservative guidelines for all termiticides. Keep the outermost leaves of garden plants at least a foot away from any soil-applied termiticide and you should be OK.

Washing

Regarding washing, your technician may want to suggest vegetable washing to a concerned customer whose nearby yard or house perimeter has been treated with an insecticide spray. Washing is a good idea whether pesticides have been used or not. The best washing technique includes a pre-rinse with a 10% vinegar solution (for germ control) followed by 30 seconds of tap water. This is a great way to remove urban dust, microorganisms and traces of pesticides from vegetable and fruit surfaces.

Would you recognize an edible plant?

Lastly, can you and your technicians tell a basil from a begonia, a mint from a marigold, or a pear from a poplar? Any applicator wanting to follow label directions around a home needs to be aware of what plants are present. We all don't have to be botanists, or know all the local tree species; but we should recognize the most common fruit and nut trees, herbs, and vegetables. Would you know what the common herbs sage, basil or rosemary look like? Sounds like a good exercise for training day.

When visiting a residence the first time, ask your customer if they have any herbs, fruit trees, nut trees or vegetables that you need to be aware of. Today's gardeners are more likely to plant edible plants within flower gardens, so you might have a basil plant or a tomato plant growing among the daisies. Assume your customers are organic in their vegetable garden and avoid these areas accordingly.

Believe me, your customers will appreciate any extra consideration you give to their home gardens. Treat them well and they might even greet you at the door with a big bag of zucchini.

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About Me

I have served as entomology specialist for Texas AgriLife Extension since 1989. I get to work with, and for, a bunch of great people including pest management professionals, school facilities managers, extension volunteers, researchers and other extension professionals. My areas of specialty center on research on insects affecting man including spiders, scorpions, fire ants, termites and others. My program also focuses on training school maintenance professionals in principles of integrated pest management (IPM). Our goal is to make schools healthier, cleaner places to study and live.